Though we have no evidence of what to find in the wastes of Fallout 4, I put 2 and 2 together to come up with some theories on what we can expect. So Here we go...

Because it is confirmed that there is a modified Gamebryo engine that will most likely be used in Fallout 4, we can expect:

Dual-Wielding One handed weapons

Dynamic Melee Combat

Smoother Graphics, and more environmental movement

A sprint button, much like Skyrim.

These are just theories though, so don't flame me. Also, we may find Radiant AI returns from Skyrim, but its just a possibility.